1. Field of the Invention
The present invention is directed to loaders for data carriers, and in particular to a loader of the type wherein a magazine containing a plurality of data carriers is inserted into a loader housing, and a data reader is moved over the magazine to select a data carrier therefrom for insertion into the reader.
2. Description of the Prior Art
It is known to record and store data on a number of different types of storage media, such as magnetic tape, optical disks and the like. Because of the limited size of such data carriers, the amount of data which can be stored thereon is similarly limited. In computing and data retrieval systems wherein a large amount of data is stored, a relatively large number of such data carriers are required in order to contain all of the necessary data. To retrieve the data from the data carrier, it is necessary to insert the carrier into a data reader, such as a tape drive unit. (As used herein, the unit into which the data carrier is inserted will be referred to as a "reader," although it may also be used for the purpose of writing data on the carrier.)
In systems requiring multiple data carriers, it is cumbersome to manually successively insert and remove the data carriers from the reader. Many such systems, therefore, employ a data carrier magazine, which holds a large number of data carriers, with the magazine being loadable into a device which contains the reader. A selected data carrier can then be automatically removed from the magazine, and automatically inserted into the reader wherein the data on the carrier is read, or new data is written on the carrier. After completion of the read or write operation, the data carrier is then automatically removed from the reader and is replaced in the magazine. The overall unit, which includes the magazine, the data reader, and an automated mechanism for removing the data carrier from the magazine, inserting it into the reader, and removing it from the reader and replacing it in the magazine, is generically known as a "loader." Loaders can generally be classified into three types: Those in which the magazine is stationary in the loader and the drive is moved over the magazine to the position of a selected data carrier in the magazine, those wherein the reader is stationary and the magazine is moved to position a selected data carrier at a location for insertion in the reader, and those wherein both the magazine and reader are stationary, and an "elevator" or other type of data carrier transfer mechanism is used to move the selected data carrier from the magazine, transport it to, and insert it in the reader. Various combinations of these three basic types of units are also known.
A loader of the first type, wherein a plurality of data carriers, such as magnetic tape cartridges, are contained in a stationary magazine, and a tape drive unit is moved over the magazine to a position above a selected tape cartridge, is described in Japanese Patent 2-96965. In this known device, transfer of the tape cartridge from the magazine into the reader takes place by means of a mechanism which is carried by the tape drive unit and which extends below the magazine. Each cartridge receptacle in the magazine has an opening in a bottom thereof, and the mechanism carried by the tape drive unit has a rotatable threaded rod connected to a lifting element which is disposed in registry with the opening for a receptacle when the tape drive unit is positioned above that receptacle. Rotation of the threaded rod causes the lifting element to project into the opening, thereby pushing the tape cartridge upwardly out of the magazine and into the tape drive unit, at least to a sufficient extent to permit mechanics within the tape drive unit to engage the tape cartridge.
Another type of transfer mechanism for cassettes is described in Japanese Patent 1-205755. That patent discloses a cassette insertion and removal mechanism for use in a video cassette lending machine, wherein the cassette is gripped on opposite sides by respective roller-driven belts. The belts frictionally engage the cassette, and when moved by respective driven rollers about which the belts are entrained, a cartridge is removed from a location on a storage shelf. The mechanism can be operated in reverse for replacing the cassette on the storage shelf.